Since the interaction of individual variables with learning outcomes has been relatively neglected in the CLIL (Content and Language Integrated Learning) research agenda (Doiz, A., Lasagabaster, D., & Sierra, J. M. (2014). CLIL and motivation: The effect of individual and contextual variables. "The Language Learning Journal," 42(2), 209-224), this study aims to investigate the impact of CLIL programmes on gender-related differences in language and content achievement at the end of primary and compulsory secondary education. In line with previous investigations reporting a levelling effect of CLIL programmes on gender differences, this study seeks to show whether bilingual programmes may help to balance out gender differences in CLIL learning outcomes and whether the gender gap may vary across educational levels. To that end, discriminant and factor analyses were performed with the experimental (EFL + CLIL exposure) and control (EFL-only exposure) groups. The main finding was that the gender gap in CLIL learning outcomes is cancelled out, which could be ascribed to the hypothesised levelling effect of CLIL on gender differences in learning outcomes.